It works for me and without any problems (on Windows & Linux). Has it ever worked or is this a new installation? You need to update your forum profile with the output of the following command (do not post the output in this thread):

Code:

zmcontrol -v

You also haven't mentioned whether this is Linux or Windows for the client? Have you started firefox without any add-ons to see if there's something causing the problem?

This is a tough one for people to help troubleshoot. In general the arrow keys do work with both the Web Client and Zimbra Desktop. For example, I have tested on Windows XP and 7 and also Fedora 17, with Firefox, Chrome, and IE they work correctly everywhere. I don't think there is anything on the Zimbra server that you can check to see why the arrow keys aren't behaving properly.

I know you said you have tested on both a Windows and Linux client, but you also mention virtual machines. Are you always testing from the same physical system or have you tried on multiple systems? Are you using a standard keyboard and/or do you have any special keyboard mappings?